Mr. Lew instead reiterated his call for Congress to act quickly to raise the nation’s debt ceiling and reinforced that the Obama administration won’t negotiate over the borrowing limit, according to remarks prepared for a speech to the Economic Club of Washington.

The president “will not accept measures that would tie a debt limit increase to defunding or delaying the Affordable Care Act,” Mr. Lew said.

His comments put the White House on a collision course with Republicans in Congress.

House and Senate Republicans are still working to craft their strategy for dealing with the government’s borrowing limit, but many rank-and-file Republicans have said they will only vote to increase the debt ceiling or continue government spending in exchange for a delay of the Affordable Care Act. The White House has said it won’t accept such a change, but that has not deterred Republicans.

And the stare down between the White House and Republicans on the matter is only escalating.

On Monday, more than 50 House Republicans had signed onto a plan that would require a delay of the health-care law in exchange for a vote to continue funding the government. By Tuesday morning, Mr. Lew said in response to a question, “If you look at the debate over the debt limit, there’s a kind of notion in part of the House Republican caucus that it can be used as a lever to force major policy changes, like the delay of the Affordable Care Act. That’s just not reality, and they are going to have to start dealing with reality.”

Many House Republicans have dismissed the White House’s negotiating position, saying the Obama administration is not doing enough to tackle the government’s deficit. They believe Republicans must use the debt ceiling leverage to force the White House to agree to spending cuts, or no changes to the budget will be made.

The Treasury Department has told Congress that the Federal government will exhaust its ability to continue borrowing money in mid-October. At that point, the government would only have cash on hand available to finance it operations, including making interest payments on the national debt and paying Social Security, Medicare and veterans’ benefits.

Mr. Lew said it would be “very dangerous” for Congress to wait until the last minute to raise the borrowing limit, because the government could face an unexpected cash shortfall, which would put it at risk of defaulting on its obligations.

“We cannot afford for Congress to gamble with the full faith and credit of the United States of America,” he said in the speech.

But he also reiterated that the White House won’t even discuss the matter with lawmakers.

“There are not and will not be negotiations about the debt limit,” Mr. Lew said.

Separately, Mr. Lew was asked to comment on the U.S. dollar. He said he thinks “a lot” about it but declined to comment. He also declined to comment on monetary policy, or the timing of a nomination for the next Federal Reserve chairman.

About Washington Wire

Washington Wire is one of the oldest standing features in American journalism. Since the Wire launched on Sept. 20, 1940, the Journal has offered readers an informal look at the capital. Now online, the Wire provides a succession of glimpses at what’s happening behind hot stories and warnings of what to watch for in the days ahead. The Wire is led by Reid J. Epstein, with contributions from the rest of the bureau. Washington Wire now also includes Think Tank, our home for outside analysis from policy and political thinkers.